In recent years, a self-propelled X-ray Computed Tomography (CT) apparatus (hereinafter referred to as an “X-ray CT apparatus”) has become popular and is used in combination with an X-ray diagnosis apparatus in a surgical scene, etc. A self-propelled X-ray CT apparatus includes a gantry configured to image a subject. The bottom of this gantry is provided with a carrier unit that is moved along a rail disposed on a floor. The self-propelled X-ray CT apparatus can move the gantry to a desired position by moving the carrier unit along the rail.
The top of the rail is provided with a rail cover for preventing the rail from getting soiled with a chemical used in an operation, blood, etc. In the case of moving the gantry along the rail, the carrier unit is moved through a space between the rail and the rail cover. That is, in order to move the carrier unit along the rail, a gap needs to be formed between the rail and the rail cover. On the other hand, since a floor of examination room gets dirty by an operation, etc., a rail is required to have a waterproof property so that the floor can be cleaned by spreading water. However, the existence of a gap between the rail and the rail cover incurs a risk that water enters into the rail through the gap.